Method for configuring a module for detecting the switching of a valve in an oil circulation circuit

Abstract

Method for configuring a module for detecting the switching of a valve in an oil circulation circuit. Method for configuring a module for determining an oil pressure model for detecting the switching of a valve (113) in an oil circulation circuit (111) in an aircraft turbomachine (110) (100), the method comprising: determining an oil pressure model in the circulation circuit when the valve of the oil circulation circuit has switched and the oil temperature in the circulation circuit is above a first threshold, the oil pressure model being stored in the determination module; and determining a set of functions from the differences between the determined oil pressure model and an oil pressure during an aircraft flight, the set of functions (F) being stored in the determination module. Figure for the abstract: Fig. 1

Description

Title of the invention: Method for configuring a module for detecting switching of a valve of an oil circulation circuit Technical field

[0001] The present invention relates to the general field of valves present in an aircraft turbomachine oil circulation circuit and more particularly to the detection of switching of an exchanger valve of an oil circulation circuit in an aircraft turbomachine. Prior art

[0002] In a gas turbine, the engine bearings are lubricated and cooled using oil circulating in a specific circuit. As the oil heats up, it must be cooled to prevent coking. For this, exchangers are used which use a second heat transfer fluid, such as the fuel injected into the turbomachine or the cold air entering the turbomachine, which will cool the oil. Then, when the oil cools, it becomes viscous and circulates less well in its circulation circuit.

[0003] Thus, the oil has an optimum temperature range allowing it to fulfill its cooling and lubrication functions for the turbomachine engine bearings. Below its minimum temperature, it is preferable for it to heat up to return to its operating range, and therefore for the exchanger to be inactive; whereas above its maximum temperature, the exchanger must be active to cool it. Generally, in addition to an oil / fuel exchanger already present in the oil circulation circuit, an oil / air exchanger is added to cool the oil. A valve is then used at this oil / air exchanger which will switch at a given oil temperature to bypass or not this additional exchanger.So, when the oil cools down (its temperature is for example below 75°C), the valve allows the additional exchanger to be bypassed so as not to cool the oil too much, and when the oil heats up (its temperature is for example above 75°C), the valve is switched so that the oil passes into the additional exchanger.

[0004] The exchanger switching valve is not controlled because its switching is passive and depends on the temperature of the oil passing through it. The position of the valve is neither controlled nor measured, which prevents its proper operation from being monitored. Several failure modes of the oil circuit can thus occur: the valve can fail in the open or closed position or it can become obstructed.

[0005] To detect these failures, it is possible to add a measurement of the valve position, but this involves the addition of at least one sensor and electrical wires connecting the sensor to the control system of the turbomachine. Such a valve position sensor increases the complexity and bulk of the system, and induces a potential risk of additional error in the measurements provided by this additional position sensor.

[0006] It is still possible to use a model of the oil circulation system in nominal operation where any deviation between the actual measurements and the model can be considered as a signal of valve failure. However, in the case where the valve is linked to an exchanger, a model representing a circuit with an exchanger and a circuit without an exchanger is required. However, without knowing the position of the valve (open or closed), it is not possible to create a model representing the two possible circuits.

[0007] It is therefore desirable to have a new method for detecting the switching of a valve in order to detect potential failures without requiring a direct measurement of the position of the valve. Statement of the invention

[0008] The invention relates to a method for configuring a module for determining an oil pressure model for detecting switching of a valve of an oil circulation circuit in an aircraft turbomachine, the configuration method comprising: a determination of an oil pressure model in the oil circulation circuit of the turbomachine when the valve of the oil circulation circuit has switched and a temperature of the oil in the circulation circuit is greater than a first threshold, the oil pressure model being recorded in the determination module; and a determination of a set of functions from differences between the determined oil pressure model and an oil pressure during a flight of the aircraft, the set of functions being recorded in the determination module.

[0009] The configuration method of the invention thus exploits a modeling defect introduced voluntarily (in the step of determining the oil pressure) by limiting the validity of the oil pressure model over an operating range in which the position of the valve in nominal operation is certain. Thanks to this, the signature of the switching of the valve is amplified and can be visible in the functions of the set of determined functions. A switching defect can thus be detected at the beginning of the occurrence of the failure, i.e. when the valve begins to fail to open and / or close completely.

[0010] According to a particular characteristic of the invention, the first threshold is between 80°C and 90°C. It is for example equal to 85°C.

[0011] This range of values, and more particularly the value of 85°C, corresponds to the temperature at which the valve is switched and the oil is cooled by the heat transfer fluid of the exchanger.

[0012] According to another particular characteristic of the invention, the set of functions is determined by a decomposition of the differences into shapes by the Shapelets method.

[0013] Another object of the invention is a method for detecting the switching of a valve of an oil circulation circuit in an aircraft turbomachine, the method comprising: - measurements of oil pressure in the circulation circuit; - a determination of differences between said oil pressure measurements and an oil pressure from the model recorded in a determination module configured according to the configuration method according to the invention; and - a detection of the switching of the valve, implemented by a detection module, based on a comparison between a set of functions and said determined differences, the set of functions being recorded in a determination module configured according to the configuration method according to the invention.

[0014] Thanks to the invention, a valve switching problem can be suspected when the oil pressure measurements do not correspond to one of the functions determined by the determination module.

[0015] In addition, the method does not include any measurement of the position of the valve, which makes it possible to avoid the addition of a position sensor at the valve.

[0016] According to a particular characteristic of the invention, the oil pressure measurements are carried out when the temperature of the oil is within a first range of values, which is for example defined between 70°C and 85°C.

[0017] This range of values ​​corresponds to the oil temperatures around which the valve switches in nominal operation to include or not include the oil / air exchanger in the oil circulation circuit. Generally, the circulation circuit passes through a single exchanger (fuel / oil exchanger) for temperatures below approximately 75°C and passes through two exchangers (the oil / air exchanger is introduced) thanks to the switched valve for temperatures above approximately 75°C to prevent the oil from heating up too much.

[0018] According to another particular characteristic of the invention, the oil pressure measurements are carried out when the speed of the turbomachine is within a second range of values, which is for example defined between 60% and 80% of the nominal speed of the turbomachine.

[0019] Another object of the invention is a device for detecting the switching of a valve of an oil circulation circuit in an aircraft turbomachine comprising - a determination module configured to determine an oil pressure model when the valve is open and an oil temperature above a first threshold, and to determine a set of functions from differences between the determined oil pressure model and an oil pressure for a flight of an aircraft, and - a valve switching detection module configured to detect valve switching by comparing said set of functions with differences between oil pressure measurements and an oil pressure from said model.

[0020] According to a particular characteristic of the invention, the determination module is configured by a configuration method according to the invention.

[0021] According to another particular characteristic of the invention, the determination module comprises a neural network.

[0022] By "neural network", reference is made here to an artificial neural network thus comprising a set of artificial neurons connected to each other, an artificial neuron making it possible to determine an activation function of weighted and combined inputs.

[0023] The neural network is for example of the multi-layer perceptron type, for example with four layers.

[0024] Another object of the invention is an oil circulation circuit comprising an oil / fuel exchanger, an oil / air exchanger, a valve configured to circulate or not circulate the oil in the oil / air exchanger, a detection device according to the invention and at least one oil pressure sensor configured to acquire said oil pressure measurements.

[0025] Another subject of the invention is an aircraft comprising a turbomachine, an oil circulation circuit according to the invention and a detection device according to the invention configured to detect a switching of a valve of said oil circulation circuit.

[0026] Yet another subject of the invention is a computer program comprising instructions for implementing steps of a configuration method according to the invention, when said computer program is executed by at least one processor.

[0027] The computer program may be formed from one or more stored sub-parts in the same memory or in separate memories. The program may use any programming language, and be in the form of source code, object code, or code intermediate between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0028] Another object of the invention is a computer-readable information medium comprising a computer program according to the invention.

[0029] The information carrier may be any entity or device capable of storing the program. For example, the carrier may comprise a storage means, such as a non-volatile memory or ROM, for example a CD-ROM or a microelectronic circuit ROM, or a magnetic recording means, for example a floppy disk or a hard disk.

[0030] On the other hand, the storage medium may be a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by a telecommunications network or by a computer network or by other means. The program according to the invention may in particular be downloaded onto a computer network. Alternatively, the information medium may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question. Brief description of the drawings

[0031] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate exemplary embodiments thereof which are not in any limiting nature.

[0032] [Fig-1] [Fig.l] represents, in a schematic and partial manner, an example of software and hardware architecture of an aircraft comprising an oil circulation circuit and a detection device according to one embodiment of the invention.

[0033] [Fig.2] [Fig.2] represents, schematically and partially, an example of functional architecture of a detection device according to an embodiment of the invention.

[0034] [Fig.3] [Fig.3] schematically and partially represents a detection method according to one embodiment of the invention.

[0035] [Fig.4] [Fig.4] schematically and partially represents a configuration method according to one embodiment of the invention. Description of the embodiments

[0036] [Fig.l] represents an example of software and hardware architecture of an aircraft 100 comprising an oil circulation circuit 110 and a device 120 for detecting the switching of a valve of the oil circulation circuit according to an embodiment of the invention.

[0037] The aircraft 100 comprises a turbomachine 110 comprising an oil circulation circuit 111 comprising at least one valve 113 and a device 120 for detecting the switching of the valve 113 of the oil circulation circuit 111.

[0038] As explained in the prior art, the oil makes it possible to lubricate the engine bearings 112 of the turbomachine 110 and circulates in the circulation circuit 111 which is a specific circuit of the turbomachine 110. The valve 113 and the exchanger 114 make it possible to keep the oil within its operating temperature range to prevent it from heating up too much or becoming viscous. The heat transfer fluid of the exchanger 114 may be cold air.

[0039] The aircraft 100 also comprises an acquisition device 115 and a detection device 120.

[0040] The acquisition device 115 is configured to acquire, that is to say measure, over a determined duration, a pressure P of the oil present in the circulation circuit 111.

[0041] The acquisition device 115 comprises a pressure sensor which measures the pressure P of the oil at the valve 113. This may be a strain gauge, placed in the circulation circuit after the pump pumping the oil and before the nozzles, for example after the exchanger 114.

[0042] The acquisition device 115 may comprise an acquisition chain capable of digitizing (or even amplifying and filtering) the (analog) signal acquired by the pressure sensor.

[0043] The detection device 120 is configured to detect the switching of the valve 113 and comprises a processing unit or processor 130 and at least one memory 140.

[0044] More particularly, the detection device 120 has, according to one embodiment, the hardware architecture of a computer. As such, the detection device 120 may comprise a processor 130, a random access memory, a read-only memory 140, and a non-volatile memory. The read-only memory 140 associated with the detection device 120 constitutes an information medium in accordance with the invention, readable by a computer and by the processor 130, on which a computer program 141 in accordance with the invention is recorded. The computer program 141 comprises instructions for carrying out steps of a detection method in accordance with the invention and implemented by the detection device 120, when the computer program 141 is executed by the processor 130.

[0045] The computer program 141 defines functional and software modules of the detection device 120 described below with reference to [Fig.2].

[0046] The detection device 120 may also comprise a communication module 150 configured to communicate with the acquisition device 115. The communication interface between the detection device 120 and the acquisition device 115 may be wired or wireless, and may implement any protocol known to those skilled in the art.

[0047] [Fig. 2] represents an example of functional architecture of a device 120 for detecting the switching of a valve of an oil circulation circuit according to an embodiment of the invention.

[0048] Generally, the detection device 120 comprises modules respectively configured to implement each of the steps of a detection method according to the invention.

[0049] In particular, and as illustrated in [Fig.2], the detection device 120 comprises, according to one embodiment, at least: - a determination module 121 configured to determine an oil pressure when the valve of the circulation circuit has switched and an oil temperature Thuiie in the circuit is greater than a first threshold Tseuii and to determine a set of functions F from differences between the determined oil pressure and an oil pressure during a flight of the aircraft; and - a detection module 122 configured to detect a switching of the valve by comparing oil pressure measurements P with the set of functions F.

[0050] The determination module 121 may comprise a neural network. Generally, a neural network comprises one or more layers of artificial neurons connected to each other. An artificial neuron is configured to perform the following operations. A neuron takes one or more values ​​as input and weights these inputs by coefficients called weights. The neuron combines the weighted inputs as well as a bias, typically this combination operation is a sum, or a norm. This combination is then provided as input to an activation function. Examples of commonly used activation functions are the sigmoid, ReLU (acronym for "Rectified Linear Unit"), and hyperbolic tangent functions. Finally, the output of the artificial neuron is the result of the activation function.In the context of a neural network, the parameters of the network include a varied set of parameters, such as weights, biases, and activation functions used for the different neurons of the network. These parameters thus make it possible to optimize the network to implement the determination of the set of functions F as fine as possible. The types of neural networks capable of implementing the determination module 121 of the invention are varied, and are for example multilayer perceptrons, convolutional or convolutional neural networks, recurrent neural networks, etc.

[0051] The term module can correspond to a software component as well as to a hardware component or a set of hardware and software components, a software component itself corresponding to one or more computer programs or sub-programs or more generally to any element of a program capable of implementing a task or a set of tasks as described for the modules concerned. In the same way, a hardware component corresponds to any element of a hardware assembly capable of implementing a task or a set of tasks for the module concerned (integrated circuit, smart card, memory card, etc.).

[0052] [Fig. 3] schematically represents a method 300 for detecting the switching of a valve of an oil circulation circuit according to an embodiment of the invention. More precisely, this [Fig. 3] presents an operation that can be implemented by the detection device 120 of FIGS. 1 and 2.

[0053] The detection method 300 comprises at least the steps 310 to 330 described below and implemented by the detection device 120 of FIGS. 1 and 2.

[0054] During step 310, the detection device 120 obtains the oil pressure measurements P in the circulation circuit. In particular, it can obtain these measurements when the oil temperature Thuiie is within a first range of values ​​[Ti; T2], for example between 70°C and 120°C, and more particularly between 70°C and 85°C, and / or when the speed v of the turbomachine is within a second range of values ​​[vi; v2], for example between 60% and 80% of the nominal speed of the turbomachine.

[0055] The speed v corresponds for example to the speed of the high pressure body of the turbomachine, because the high pressure body is the one which has the greatest influence on the oil pressure of the circulation circuit. The second range of values ​​[vi; v2] corresponds to idling on the ground during which the speed of the high pressure body is stabilized and the temperature of the oil Thuiie reaches a bearing temperature which causes the valve 113 to switch. The bearing temperature is included in the first range of values ​​[Ti; T2] therefore for example between 70°C and 120°C.

[0056] The detection device 120 can obtain the oil pressure P measurements directly from the acquisition device 115 or indirectly via its communication module 150.

[0057] During step 320, the detection device 120 determines differences A between the oil pressure measurements P measured in step 310 and an oil pressure P huiie determined in the circulation circuit when the valve 113 has switched and the oil temperature Thuiie of the circuit 111 is greater than a first threshold Tseuii- The first threshold Tseuii represents the temperature at which it is considered that the oil is heating up and that the valve has switched. Said threshold Tseuii is for example between 80°C and 90°C, for example equal to 85°C.

[0058] During step 330, the detection device 120 compares the differences A determined in step 320 with the set of functions F determined by the determination module 121 and detects a switching of the valve if the pressure measurements P correspond to one of the functions F. Indeed, when the circulation circuit 111 changes state (i.e. the valve 113 switches and the exchanger 114 is then included in the circuit 111), we go from an incorrectly modeled oil pressure P to a correctly modeled pressure, so the difference between the two has a “jump”. It is this jump, representing the switching of the valve 113, that we seek by comparing the pressure measurements P with the set of functions F.

[0059] [Fig.4] schematically represents a configuration method 400 of the determination module 121 and the manner in which the set of functions F is determined.

[0060] During step 410, the oil pressure Phuiie in the circulation circuit 111 is determined when the valve 113 has switched (i.e. the exchanger 114 belongs to the circuit 111) and the oil temperature Thuiie of the circuit 111 is greater than a first threshold Tseuii- The first threshold Tseuii represents the temperature at which it is considered that the oil is heating up and that the valve has switched. It is for example between 80°C and 90°C, for example equal to 85°C.

[0061] During step 420, a set of functions F is determined from the differences between the oil pressure Phuiie determined during step 410 and an oil pressure during a flight of the aircraft 100.

[0062] The set of functions F may comprise a number of functions between 5 and 20, for example here 10 functions each comprising 400 points, the points being the difference between the oil pressure Phuiie determined during step 410 and an oil pressure during a flight of the aircraft for 400 different instants as a function of time.

[0063] The set of functions F is for example determined by a decomposition of the differences into shapes by the Shapelets method.

[0064] The Shapelets method is more particularly described in the documents “Time-series shapelets: a new primitive for data mining” by L. Ye and E. Keogh, SIGKDD, 2009 and “Learning Time-Series Shapelets” by J. Grabocka et al., SIGKDD, 2014.

[0065] The Shapelets method is for example implemented from a hundred time series of 2000 points each, the series representing the difference between the oil pressure determined in step 410 and an oil pressure during a flight of the aircraft. Among these hundred time series, at least half represents said difference during a switching of the valve. For example, the Shapelets method is implemented for 144 time series, 72 of which represent the com- valve mutation.

[0066] These two methods make it possible to characterize the set of functions F into shapes, but more particularly, it is possible to characterize the amplitude of the shapes, their duration, their maximum value, etc., and to follow these characteristics over time. A change in these characteristics over time can be an indicator of the state of the valve (appearance of a fault such as incomplete opening or closing, or longer opening or closing, etc.). It is also possible, in addition to comparing the measured oil pressure P with the set of functions F, to follow over time the temperature of the oil at which the switching of the valve 113 is detected.

[0067] The configuration method 400 may also comprise post-processing of the differences between the oil pressure Phuiie determined in step 410 and an oil pressure during a flight of the aircraft, in order to filter out sudden variations over time which are due to modeling defects in step 410 in the transient zones of the influence quantities, such as the speed of the high-pressure body of the turbomachine. Indeed, when the turbomachine is in a transient phase (acceleration or deceleration), there may be sudden variations in the differences determined in step 410 which may then induce errors in the step of detecting the switching of the valve. The post-processing step, and more particularly the filtering, may, for example, be carried out as soon as the speed of the high-pressure body exceeds a threshold, for example 80 revolutions per second squared.

[0068] It should be noted that the order in which the steps of a method according to the invention are carried out, in particular with reference to Figures 3 and 4, constitutes only an exemplary embodiment without any limiting character, variants being possible. In particular, a method according to the invention may comprise one or more iterations of the steps described above, in particular with reference to the attached figures.

Claims

Claims

1. Method for configuring (400) a module for determining (121) an oil pressure model (Phuiie) for detecting switching of a valve (113) of an oil circulation circuit (111) in a turbomachine (110) of an aircraft (100), the configuration method comprising: - determining (410) an oil pressure model (Phuiie) in the oil circulation circuit (111) of the turbomachine (110) when the valve (113) of the oil circulation circuit has switched and an oil temperature (T oil) in the circulation circuit is greater than a first threshold (Tseuii), the oil pressure model being recorded in the determination module (121); and - a determination (420) of a set of functions (F) from differences between the determined oil pressure model and an oil pressure during a flight of the aircraft, the set of functions (F) being recorded in the determination module (121).

2. The configuration method of claim 1, wherein the first threshold is between 80°C and 90°C.

3. A configuration method according to any one of claims 1 or 2, wherein the set of functions is determined by a decomposition of the differences into shapes by the Shapelets method.

4. Method for detecting (300) the switching of a valve (113) of an oil circulation circuit (111) in a turbomachine (110) of an aircraft (100), the method comprising: - measurements (310) of an oil pressure (P) in the circulation circuit; - a determination (320) of differences (A) between said oil pressure measurements and an oil pressure (Phuiie) from the model recorded in a determination module (121) configured according to the configuration method of any one of claims 1 to 3; and - a detection (330) of the switching of the valve, implemented by a detection module (120), as a function of a comparison between a set of functions (F) and said determined differences (A), the set of functions being recorded in a determination module (121) configured according to the method of any one of claims 1 to 3.

5. Device (120) for detecting the switching of a valve of an oil circulation circuit in an aircraft turbomachine comprising: - a determination module (121) configured to determine an oil pressure model (Phuiie) when the valve has switched and an oil temperature greater than a first threshold (Tseuii), and to determine a set of functions (F) from differences between the determined oil pressure model and an oil pressure for a flight of the aircraft; and - a detection module (122) of the switching of the valve configured to detect the switching of the valve by comparing said set of functions (F) with differences (A) between oil pressure measurements and an oil pressure from said model.

6. A detection device according to claim 5, wherein the determination module is configured by a configuration method according to any one of claims 1 to 3.

7. Detection device according to any one of claims 5 or 6, wherein the determination module comprises a neural network.

8. Oil circulation circuit (111) comprising an oil / fuel exchanger, an oil / air exchanger (114), a valve (113) configured to circulate or not circulate the oil in the oil / air exchanger (114), a detection device (120) according to any one of claims 5 to 7 and at least one acquisition device (115) configured to acquire said oil pressure measurements (P).

9. Aircraft (100) comprising a turbomachine (110), an oil circulation circuit (111) according to claim 8 and a detection device (120) according to any one of claims 5 to 7 configured to detect a switching of a valve (113) of said

10. traffic circuit. Computer program (141) comprising instructions for implementing steps of a configuration method according to any one of claims 1 to 3, when said computer program (141) is executed by at least one processor (130).

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